Fade Particle to black

Apprentice

Posts: 9
Joined: 2010.02

Post: #1

Apr 2, 2008 — 10:46 AM

hi,
anyone know to how i can fade a particlecolor from red (for example) to black?
Fading works with all colors except black.
I have testet all blending-types, but nothing works.

here is my code

Code:

float r = p[i].startColor.r + (p[i].timeAlive / p[i].lifeTime) * (p[i].endColor.r - p[i].startColor.r);

float g = p[i].startColor.g + (p[i].timeAlive / p[i].lifeTime) * (p[i].endColor.g - p[i].startColor.g);

float b = p[i].startColor.b + (p[i].timeAlive / p[i].lifeTime) * (p[i].endColor.b - p[i].startColor.b);

glColor4f(r, g, b, 1.0);

OneSadCookie

Luminary

Posts: 5,143
Joined: 2002.04

Post: #2

Apr 2, 2008 — 11:16 AM

I don't see why that wouldn't work. What's the problem?

bonanza

Apprentice

Posts: 9
Joined: 2010.02

Post: #3

Apr 2, 2008 — 11:28 AM

OneSadCookie Wrote:I don't see why that wouldn't work. What's the problem?

when fade to black, the particles fade out (transparent) but they should fade to black

Fenris

Oldtimer

Posts: 834
Joined: 2002.09

Post: #4

Apr 2, 2008 — 11:37 AM

Are you in GL_SRC_ALPHA, GL_ONE blend mode?

(Latest post: 16 Steps to Infinity)

bonanza

Apprentice

Posts: 9
Joined: 2010.02

Post: #5

Apr 2, 2008 — 11:38 AM

Fenris Wrote:Are you in GL_SRC_ALPHA, GL_ONE blend mode?

I have testet all blending-combinations, nothing works

OneSadCookie

Luminary

Posts: 5,143
Joined: 2002.04

Post: #6

Apr 2, 2008 — 12:44 PM

Should be ONE, ONE_MINUS_SRC_ALPHA or SRC_ALPHA, ONE_MINUS_SRC_ALPHA depending on whether the underlying texture is premultiplied or not. Make sure the texture environment is set to MODULATE.

Nothing in what you've posted indicates why it would become transparent.

bonanza

Apprentice

Posts: 9
Joined: 2010.02

Post: #7

Apr 2, 2008 — 09:57 PM

Thanks for reply.
Texture-Environment is setup correctly.
Here a screenshot of what i get
[Image: blend.jpg]

blendmodes:

Code:

glDepthMask(GL_FALSE);

glEnable(GL_BLEND);

glBindTexture(GL_TEXTURE_2D, texture);

//glBlendFunc(GL_SRC_ALPHA, GL_ONE);

//glBlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ONE);

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

render...

Fenris

Oldtimer

Posts: 834
Joined: 2002.09

Post: #8

Apr 3, 2008 — 04:57 AM

It looks to me as if there's no alpha channel on the particle?

(Latest post: 16 Steps to Infinity)

bonanza

Apprentice

Posts: 9
Joined: 2010.02

Post: #9

Apr 3, 2008 — 05:24 AM

I have testet textures with alpha-channel but no luck:
[Image: pic.jpg]

here is the effect what i want (fade from brown to black, and fade out)

[Image: test.jpg]

This is my textur:
$[Image: tex.jpg]$

This is my new code:

Code:

float r = _p[i].startColor.r * (1-(_p[i].age / _p[i].maxAge) ) + _p[i].endColor.r * (_p[i].age / _p[i].maxAge);

float g = _p[i].startColor.g * (1-(_p[i].age / _p[i].maxAge) ) + _p[i].endColor.g * (_p[i].age / _p[i].maxAge);

float b = _p[i].startColor.b * (1-(_p[i].age / _p[i].maxAge) ) + _p[i].endColor.b * (_p[i].age / _p[i].maxAge);            

float alpha = (_p[i].age / _p[i].maxAge);

glColor4f(r,g,b, 1- alpha);

Possibly Related Threads...

Thread:		Author	Replies:	Views:	Last Post
	Discrad black parts in texture	bonanza	7	5,611	Oct 27, 2011 01:05 AM Last Post: bonanza
	Problems trying to fade in windowed mode	Wowbagger	4	3,661	Aug 13, 2007 12:11 PM Last Post: Wowbagger
	how to make a RGBA image fade away?	WhatMeWorry	7	4,362	Nov 13, 2006 07:58 PM Last Post: akb825
	Particle Engine	bronxbomber92	9	3,734	Oct 16, 2006 03:44 PM Last Post: bronxbomber92
	Particle trails	LongJumper	6	3,249	Jun 29, 2005 12:42 AM Last Post: LongJumper